Courtesy of the University of Manchester
and World Science staff
New 3D film clips show what happens as a brain goes unconscious-offering scientists what they call an unprecedented peek into the physical nature of that mysterious state, consciousness.
Reasoning that useful insights could come from anything that shows what separates consciousness from unconsciousness, researchers filmed brains with a new type of scanning device while an anesthetic took effect on volunteers.
Reasoning that useful insights could come from anything that shows what separates consciousness from unconsciousness, researchers filmed brains with a new type of scanning device while an anesthetic took effect on volunteers.
| |
An image from the fEITER brain scanning device. (Courtesy U. of Manchester) |
Anesthesiologist Brian Pollard of the University of Manchester, U.K. said the real-time images seem to show that losing consciousness involves a change in electrical activity deep in the brain. The process alters the activity of certain groups of nerve cells and hinders communication between different parts of the brain, he explained.
He added that the findings seem to support a hypothesis put forward by Susan Greenfield of the University of Oxford about the nature of consciousness. Greenfield suggests consciousness arises from different groups of brain cells, called neural assemblies, that work efficiently together, or not, depending on the available stimulations. Consciousness is not an all-or-none state but more like a dimmer switch, she argues, changing according to growth, mood or drugs.
When someone is anesthetized, Pollard said, it seems small neural assemblies either work less well together or inhibit communication with other neural assemblies. "Our findings suggest that unconsciousness may be the increase of inhibitory assemblies across the brain's cortex," the outer and more advanced region of the brain, he said. "These findings lend support to Greenfield's hypothesis."
The team used a new imaging method, invented at the university, whose name is a mouthful even by the standards of the already long acronyms now used for some brain-scanning tehniques. It's called functional electrical impedance tomography by evoked response, or fEITER. It's designed to enable high-speed imaging and monitoring of electrical activity deep within the brain.
"We have looked at 20 healthy volunteers and are now looking at 20 anesthetized patients scheduled for surgery," said Pollard, who presented results at the European Anaesthesia Congress in Amsterdam June 11. "We are able to see 3-D images of the brain's conductivity change, and those where the patient is becoming anesthetized are most interesting."
"We have been able to see a real time loss of consciousness in anatomically distinct regions of the brain for the first time," he added. "We still do not know exactly what happens within the brain as unconsciousness occurs, but this is another step in the direction of understanding the brain and its functions."
The new imaging method could "make a huge impact on many areas of imaging in medicine. It should help us to better understand anesthesia, sedation and unconsciousness, although its place in medicine is more likely to be in diagnosing changes to the brain that occur as a result of, for example, head injury, stroke and dementia," he added. "The biggest hurdle is working out what we are seeing and exactly what it means."
He added that the findings seem to support a hypothesis put forward by Susan Greenfield of the University of Oxford about the nature of consciousness. Greenfield suggests consciousness arises from different groups of brain cells, called neural assemblies, that work efficiently together, or not, depending on the available stimulations. Consciousness is not an all-or-none state but more like a dimmer switch, she argues, changing according to growth, mood or drugs.
When someone is anesthetized, Pollard said, it seems small neural assemblies either work less well together or inhibit communication with other neural assemblies. "Our findings suggest that unconsciousness may be the increase of inhibitory assemblies across the brain's cortex," the outer and more advanced region of the brain, he said. "These findings lend support to Greenfield's hypothesis."
The team used a new imaging method, invented at the university, whose name is a mouthful even by the standards of the already long acronyms now used for some brain-scanning tehniques. It's called functional electrical impedance tomography by evoked response, or fEITER. It's designed to enable high-speed imaging and monitoring of electrical activity deep within the brain.
"We have looked at 20 healthy volunteers and are now looking at 20 anesthetized patients scheduled for surgery," said Pollard, who presented results at the European Anaesthesia Congress in Amsterdam June 11. "We are able to see 3-D images of the brain's conductivity change, and those where the patient is becoming anesthetized are most interesting."
"We have been able to see a real time loss of consciousness in anatomically distinct regions of the brain for the first time," he added. "We still do not know exactly what happens within the brain as unconsciousness occurs, but this is another step in the direction of understanding the brain and its functions."
The new imaging method could "make a huge impact on many areas of imaging in medicine. It should help us to better understand anesthesia, sedation and unconsciousness, although its place in medicine is more likely to be in diagnosing changes to the brain that occur as a result of, for example, head injury, stroke and dementia," he added. "The biggest hurdle is working out what we are seeing and exactly what it means."
Source: World Science
http://www.world-science.net/othernews/110610_consciousness
http://www.world-science.net/othernews/110610_consciousness
Posted by
Robert Karl Stonjek [Thanks Art Funkhouser
Robert Karl Stonjek [Thanks Art Funkhouser
No comments:
Post a Comment